Minnesota Vikings wide receiver Mike Wallace was a mysterious absence from Vikings practice again Monday and the team isn't offering a lot of answers as to why.
Wallace had his most productive game with the Vikings during their week four loss to Denver. Wallace finished with eight catches for 83 yards and a touchdown.
But Wallace also missed the team's only practice last week and the Vikings haven't put out an injury report since.
Vikings coach Mike Zimmer didn't clear the matter any at practice.
While there hasn't been an injury report issued, Pro Football Talk notes there have been reports Wallace is dealing with a sore knee.
While that mystery remains unsolved, there were plenty of other Vikings injury notes at Monday's practice.
Center John Sullivan ran for the first time since his Sept. 9 back surgery. On Sept. 10, the team placed Sullivan on the injured reserve with designation to return list – keeping him out of action through the first eight weeks of the season.
He is eligible to return in week nine against the Rams.
"I'm certainly hoping so," Sullivan told the Pioneer Press of his return that week.
Sullivan is unable to practice until after the first six weeks have passed, but he was able to test his back with a run.
"I felt good," Sullivan said. "Just recovering. ... It's a process and I'm just following the plans that [athletic trainer Eric Sugarman] and our training staff have put in place for me."